1. Field of Invention
Micro-sampling devices are conventionally used to slice/cut, scoop, punch or bore samples from source materials such as paper, cloth, wood, gels, human and animal tissues and the like. The samples collected may undergo wet chemical treatment; may be examined microscopically, used to create tissue micro-array slides, or be further chemically analyzed by a variety of analytical equipment including pyrolysis gas chromatographs, mass spectrometers, scanning electron microscopes and Fourier infrared spectrometers.
A widely available and commonly used micro-sampling tool is the garden variety paper punch. These tools are manually operated and available a craft stores or business supply outlets. They have been routinely used to sample dried blood stored on blood cards or for sampling leaves in the study of crop genetic events. There are also dedicated, electric, automated punches, with large footprints designed for high throughput sampling. These systems require the user to manually feed a blood card which, when punched, automatically delivers the sample to an extraction vial, well plate, or other receptacle. These systems are designed for punching dried blood on archival blood cards only.
Paper sampling is used in the neonatal, forensic and genomic markets to analyze blood for a variety of components. Blood samples are collected on filter paper cards and then allowed to dry. A small disc of paper bearing blood is then punched from the card. The blood may then be analyzed for genetic events, diseases, proteins, enzymes or other specific component.
Typically punches are constructed of a punch and die. When operated they create a shearing action thereby tearing the disc of paper from the source card. Writing bond paper is lighter and therefore thinner and a more tightly woven product than filter type papers (i.e. coffee filter papers for example). With lighter bond papers, the shearing action of the punch and die during the punching operation creates little or no artifact fibres. This paper however, does not have the desired absorbent quality required to store blood. Blood samples and other related body fluids (i.e. saliva) are stored on thicker filter paper. This type of paper product is characterized by a loose fibre matrix. Therefore the punch/die shearing operation when punching a sample from such paper will result in the creation of associated artefact fibres. When punching filter paper bearing blood paper fibre artefacts bearing blood will be generated which may be transferred to the next sample punched and into the collection vial receiving the sample. Therefore conventional paper punching systems when used to sample blood cards generate artefacts which may lead to cross contamination.
Bench top, large footprint, automated electric punches have several moving parts both associated with the punching mechanism and the x-y translational stage holding plates or racks of vials below the die. With high throughput these systems generate static. The artefact fiber that are created may be controlled under certain conditions (i.e. de-ionization or other anti-static devices) or the sample may be randomly distributed and not delivered to the desired location. With increased usage static can build quickly and result in artefacts becoming airborne, resulting in carry over and cross contamination. The static may affect delivery of the punched disc down the delivery column resulting in non-delivery, sticking or delivery with a subsequently punched sample doubling up in a single vial.
The racks to receive the samples on the automated punches are positioned below a platen on which the paper sample is positioned for punching. Therefore the operator has no line of sight to confirm that the sample punched has been delivered to the correct vial and whether cross contamination has occurred.
Manual punches, if used for high throughput sampling of blood cards in place of more expensive automated systems, may result in repetitive stress injuries (RSI) over time to the wrist.
This new invention offers a combination of unique features including:                An electric motorized coring operation thereby reducing repetitive stress associated with manual punching and coring devices;        A coring mechanism and not a punch and die punching mechanism, eliminating the creation of paper fibre artifacts and associated cross contamination;        An absence of static build up, a contributing factor to potential cross contamination and carry over of artifacts to other samples or vials;        A completely open line of sight concept insuring sampling of the desired target area and correct delivery to the preferred vial location;        Increased sampling diameters made possible by a plurality of cutting sleeves and can be quickly exchanged;        A simultaneous cutting, lifting and storage of the sample from the source material;        Absence of repetitive stress injury (RSI) associated with manual punches;        Rapid change of sampling tips and tip diameters; and,        Increased throughput without a corresponding increase in the size of the unit.        
2. Description of Prior Art
Paper punches such as the Fiskars® crafters punch or other single hole stationary punches are widely available. These punches are inexpensive to purchase, simple to operate and offer a range in punch/die diameters from 1/16th inch to ¼ inch. The sample may be carefully punched from specific source materials such as paper and the sample delivered directly into the collection well or easily collected after punching with the aid of a tweezers or other forceps, and then inserted into the extraction vial. These manual punches generate little or no static compared with large automated electric punches. However, there are several limitations which make these devices a less than desirable tool for extracting dried blood samples from blood cards.
Paper punches are constructed with the punch and die open and not in contact. This is maintained by a biasing spring mechanism. This allows sample blood cards, within a limited ranges of thicknesses, to be quickly and easily inserted into the punch throat for punching. The area of interest to be punched can be quickly positioned below the base of the punch. The punch may be operated in one hand with the other hand used to hold the source card. This is a suitable method of sample extraction for low sampling programs where the source sample is of suitable thickness and surface dimension.
The punching action for this type of punch occurs when the top and bottom levers are squeezed together in one hand, using the thumb on top and the remaining fingers below. Due to the tension of the spring this operation can create fatigue in the finger, hand and wrist muscles after only a few sample punches are produced, and increase in fatigue over a lengthier period of repetitive punching. Therefore repetitive stress injury may develop quickly with this type of punch where even the smallest sampling pools to be collected become an arduous and painful task.
While the punch and die on this unit remain open at all times allowing for quick insertion of source material for sampling, the vertical height of the throat between the punch and die on these punches may not be large enough to handle some blood cards of greater thickness, or versatile to sample other materials soft enough to be sampled with this instrument but too thick to be inserted.
Another problem with these punches is that the horizontal length of the throat is limited and therefore may restrict sampling over all surface areas and locations of a particular blood card. For example, the Whatman GeneCard requires sampling with a 7.0 mm punch. The description of use states that a sample may be collected almost from the center of the card. Sampling directly from the center of the card is not possible with a conventional paper punch because the horizontal throat of the punch is less than the distance from the edge of the card to the center of the card. Therefore this type of punch is limited to sampling blood cards with surface dimensions that ensures the card can be inserted to allow the punch to reach any location on the surface where the blood may have collected.
These punches use a punch die mechanism and therefore cut samples by shearing a sample from the source material. The punch pushes the sample through the die, essentially tearing rather than cutting the sample disc. This may generate artefact fibres over time with repeated sampling of fibrous blood cards. If the die and surrounding area on the punch is left uncleaned or uncleared between samples, then these artifacts may build up and result in carry over to the next blood card and subsequently be deposited with the next sample into the extraction vial. Therefore this type of punching device lends itself to cross contamination. These types of punches are restricted in their application to primarily sampling blood cards and cannot suitably sample gels, tissue or other soft substrates. These punches have also been used in the agrosciences to study genetic events in crops such as corn, cotton, sunflower and soya plants. The leaf is inserted in the punch throat similar to a blood card. However, with crop studies, sampling from a single leaf may range from 1 to as many as 12 samples. Because plants have a liquid component in the leaves, repeated sampling allows for a build up of plant saps which cause samples to adhere to the punch and are not easily transferred through the die.
The paper punch is a very common, inexpensive sampling tool for sampling dried blood on blood cards and some other flat samples such as leaves.
Another manual paper sampling device, also inexpensive and widely available is the Harris Uni-Core (U.S. Patent Application No. 20020164272). This tool is constructed of a plastic barrel handle, a stainless steel sharpened coring tip and a spring operated ejection actuator. These coring tools are available in inside diameters ranging from 0.50 to 8.00 mm. There is no lever operation and therefore no throat. This allows such tools to sample from any location on a blood card. However, since there is no punch and die mechanism the sample must rest on a pliable support. The stainless steel end of the coring tool is pushed with one hand into the blood card, leaf sample, gel, paint chip, plastic, etc. with slight rotation and gentle downward pressure. The stainless steel tip may also be used to create custom size micro-filters from large samples of filter paper. The sharpened tip passes through the card and into the pliable under support. The cored sample is retained in the tip where it can be later ejected using the actuator.
Because of the razor sharp cutting tip and absence of lever action, repetitive stress on the hand occurs less frequently over the same sampling period when compared with sampling with a craft paper punch. However, the Uni-Core is still not suited for high throughput as repetitive stress injury will develop with prolonged use. The nature of the cutting tip allows this instrument to be used for sampling a variety of materials including gels, paint chips, food, etc., and to create custom size paper filters. This is a versatile sampling tool that can be used on a variety of samples of any surface dimension enabling sampling from any location without restriction in size or thickness.
Both the paper punch and Harris Uni-Core are manual punches and are not designed to punch or core a sample directly into a collection vial, however, the paper punch can accomplish this but not with consistent speed and repetition.
A third example of prior art is from IEM Screening Systems (Division of Fundamental Products Company). This company produces both manually operated and electric automated punching systems. The manually operated system consists of a punch which can hold a specific 96 hole blood card and a plastic 96-hole plate directly below the card. The punch automatically moves each time a sample is punched. Each sample is purportedly punched into a collection well in the plastic micro-titre plate located directly below and in registration with the paper blood card. However, delivery of sample is not visible to the operator and therefore cannot be confirmed after each operation. The sample is manually punched and drops directly into a specific extraction vial. Because of the lever action there is less associated repetitive stress injury than with the former two prior art examples, but RSI can occur with prolonged use. Again a punch and die mechanism is used and this can create artifacts and lead to cross contamination. These punches may only be used with specific cards of a corresponding horizontal surface dimension equal to that of the plate. The sample can only be punched from the center of the printed circle on the card where the blood sample has been entered. If the sample is not centre than the punch head will miss the sample. Therefore this punch mechanism requires sample cards prepared in a specific manner to ensure all samples can be reached for punching. This system is also restricted to sampling 96-spot blood cards and only samples with thicknesses equivalent to blood cards. There are similar restrictions on this sampling tool when compared with the Harris Uni-Core.
These former examples of prior art, while functional, are not suited for high throughput sampling regimes, and, with the exception of the Harris Uni-Core, may only be used with blood cards of a limited surface area and thickness. The Harris Uni-Core may be used on samples of a variety of thicknesses and horizontal surface areas.
Neonatal testing of newborns and paternity testing, as well as other large routine blood sampling programs, have necessitated the development of automated punching systems to handle large volumes of blood cards.
Several automated punching systems are available from BSD Technologies (Australia), EMI (USA), Nanometrics (USA), Biorad (USA) and Wallac (USA), Harris Multi-Punch (Canada). Each of these systems operates on a punch and die mechanism and is designed to punch a single, and sometimes two samples in rapid succession from the same blood card. These systems are only designed to sample blood cards and no other source material.
The sample must be hand fed into the punching region on the automated systems. At this point the punch may be activated with a foot pedal or by pressing a platen upon which the card rests below the punch. Depressing the platen activates the punch.
A plate of uniform footprint but with varying number of holes is positioned below the dye on the punch. After punching, the sample drops down a column into a collection well in the plate. As the next sample is positioned to be punched the plate below the punch/die is automatically moved in the horizontal plane to position the next open well to receive the next punched sample. There are no hopper feeding systems for automated feeding of cards, and therefore each card must be inserted manually. This may create a safety issue as one or both hands may be used and therefore places the operators fingers in the vicinity of the punch. If the operation is not synchronized, the pedal or platen activation may result in operator injury.
The automated punches create static, particularly under dry conditions often encountered during the drier winter months. This may affect delivery of the sample down the delivery column. As well these systems can create artefact fibers due once again to the shearing action of the punch and die which tears the sample. This may result in fibers becoming entangled with samples due to static build up and may lead to cross contamination.
The throat of these units is larger than that for the manual punches, except for the Harris Uni-Core. The thickness may also duplicate that used for paper punches but is not unlimited as is the case with the Harris Uni-Core. These systems offer increased throughput but may not offer the expected confidence that the samples generated are always delivered where expected nor that there is no cross contamination occurring between subsequent samplings. Contamination becomes a chronic condition of these sampling tools which is not always easy to monitor nor are the systems designed to monitor the creation and dispersion of such artifacts.
The new invention combines several features in the prior art. The new invention continues to use the same sharpened coring tip that is used on the Harris Uni-Core. This ensures that a sample from the source material is cut and not sheared or torn, and therefore does not generate artifact contaminant fibres. The new invention is electric and a motor turns the coring tip. This is now a semi-automatic system similar to the electric punching units mentioned in the prior art. However, because there is no punching and therefore fewer moving parts in contact there is little or not static created. Therefore the new invention is electric but does not generate the associated static characteristic of the larger electric automated punching systems. The motorized coring operation eliminates the need to rotate the coring barrel as is required on the Harris Uni-Core. Therefore there is reduced RSI. The unit may be operated in one hand thereby allowing the sample to be positioned with the other hand, similar to the automated systems. However, the new invention is not a punch and therefore the sample is not directed into an unseen collection vial or well. Instead the sample is retained in the coring tip as occurs with the prior art Harris Uni-Core. The sample may now be directed into a well or vial and the operator can visually confirm delivery, which is not possible on the prior art automated punching systems. As the new invention is electric it is designed to allow the operator to process more cards with minimal RSI. As the new invention uses a coring tip and is not restricted by a throat as occurs on stationary paper punches, the new invention may sample any location on samples of unlimited surface size. The tips are disposable and can be easily replaced which is not possible with the prior art manual or automated punching systems. This new invention is designed to further reduce RSI by being contoured to be held in a familiar position in the hand similar to holding an automated/manual pipette (i.e. Eppendorf® pipette) or a video game joystick.
The distal sharpened edge of the tubular cutting sleeve passes through the source material and cuts into the backing support. This operation, in combination with the backing support, forces the extracted sample to be subsequently lodged in the distal end of the tubular cutting sleeve. The sample is then dislodged from temporary storage by forcing it out with an ejection rod.
There are disadvantages with the prior art coring tools, most notably the susceptibility of the operator to Repetitive Stress Injury (RSI) and more specifically Carpal Tunnel Syndrome (CTS), a condition which interferes with the use of the hand and is caused when too much pressure is put on the nerve that runs through the wrist. Even minimal use of the manual coring device over short periods of time has lead to reported wrist discomfort. This discomfort is acerbated when the manual coring device is used in high throughput sampling environments requiring extended daily use by a single operator. The mild, periodic discomfort may lead to more chronic pain such as arthritis. The operation of the manual coring tool requires finger gripping, downward vertical wrist pressure and repeated lateral turning of the wrist in a semi clockwise/counterclockwise direction.
The new invention incorporates the original unique properties of the prior art manual coring tool but has been ergonomically designed to reduce and/or eliminate RSI and CTS. The tubular cutting tip is operated from an electric drive, rotating the tubular cutting sleeve thereby eliminating lateral rotation of the wrist. The wrist does not become fatigued and sore thereby increasing continual use of the instrument. The wrist remains in the preferred neutral straight position when operating the motor driven coring device. Vertical downward motion translation is minimal as the design of this new invention places the cutting edge of the tubular cutting tip in close proximity to the surface of the source material to be sampled. The rotation of the cutting sleeve by the electric motor greatly reduces the required downward pressure, as the sharp edge of the tubular cutting sleeve slices through the source material with minimal contact force. The hollow clamshell handle is vertical and can be held comfortably in either hand. The tubular handle rests in the palm of the hand, and is contoured to accommodate the fingers. There is a thumb rest on the reverse to rest the thumb when not punching or ejecting. At the base of the clamshell handle there is a transverse widening of the body. This allows the base of the hand gripping the instrument to rest on this flange. This hand rest at the base also acts to provide support and protection against the hand slipping into the rotating sample sleeve. The tubular handle is modeled after the familiar joystick design. The wide use of joysticks for extended video gaming has resulted in the evolution of an ergonomic design that minimizes RSI. The rotation of the tubular cutting sleeve is driven by two spur gears juxtaposed within the hollow clamshell. The motor output shaft is mated to a step down spur gear which reduces the speed of rotation of the output shaft. The electric driven tubular cutting sleeve offers the necessary means to conduct high throughput sampling over extended daily periods with minimal or no development of RSI. This high throughput is synonymous with that expected from the electric punch devices discussed earlier. The sharp edge of the tubular cutting sleeve combined with the motor driven rotation of the tubular cutting sleeve reduces the required downward pressure commonly needed and applied when using the manual coring tools. The motor driven cutting sleeve will also allow for cutting of thicker substrate materials without the required downward pressure used with the manual coring tools.
In this new invention, as with the prior art, the sample sleeve serves both as a cutting tool and as a temporary storage receptacle to retain the sample and should be replaced frequently to ensure a sharp edge. The sample ejection system enables quick, safe and clean removal of the sample from the cutting sleeve, either in a rapid action for quick throughput into a collection vial, or more slowly, to position sample on a sampling stage. The electric drive minimizes physical exertion and the contoured surfaces of the clamshell handle are ergonomically designed to fit the hand. The combination of these two characteristics enables the tool to be used in that position for extended periods, with minimal RSI risks. Sample sleeves are held in the drive shaft with a collet system so as to be easily removable for size changes; sterilization or replacement. A single dedicated ejection rod is used in association with a range of different diameter sample sleeves.
This motor driven sampling device was designed for high throughput sampling of dried blood on blood cards or sampling of any other material on media or in situ. Prior art describes a manually operated coring tool which requires finger, hand and wrist movement to core a sample. When used in high throughput sampling regimes this can, and does, lead to repetitive stress injury (RSI). This new electric coring tool has been ergonomically designed to reduce and eliminate RSI from occurring as a result of long term repeated coring operations. The tool rests comfortably in the hand and is gripped by the entire hand encircling the tubular handle. With the finger resting in front, the thumb resting on top and the base of the hand resting on an enlarged rest area at the base, similar to holding a video game joystick.
The hollow tip on this new invention allows for the collection of many samples unlike that of the automated punching system.
Replacement of sample sleeves is realized by a spindle lock mechanism which allows the collet nut to be loosened. The tip slides out and a new tip is inserted. The drive shaft incorporates a shoulder so that the sample sleeves are consistently installed to the same position. The collet nut is finger tightened to lock the tip in position. The ejection rod remains inside the sample sleeve until ejection is required.
A search did not disclose any prior art electric coring tools for sample collecting. One reference refers to a prior patent application for a manual coring tool (Harris). A second patent refers to a battery operated coring tool for coring vegetables and fruits (Dolah).
Canadian Patent Application
2,345,911 Harris
United States
U.S. Pat. No. 5,852,875 Dolah